The greenhouse and enhanced greenhouse effects refer to the return of approximately percent and greater than percent of the heat radiated by Earth.

The greenhouse and enhanced greenhouse effects refer to the return of approximately 80 percent and greater than 80 percent of the heat radiated by Earth.

Explanation:

During natural greenhouse effect :

. Solar radiation reaches the earth

. Re-radiation of heat occurs

. Less re-emitted heat

. More heath escapes into space

Hence the greenhouse effect refers to return of 80% of heat radiated by Earth.

While during Human Enhanced Greenhouse effect :

. Solar radiation reaches earth

. Re-radiation of heat occurs

. More re-emitted heat

. Less heat escapes into space

Hence the enhanced greenhouse effect refers to return of more than 80% of heat radiated by Earth .

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.